Alright, let's solve this problem step by step. We have 51 and 7702 and we're adding them together.

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 5.

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

Step 4: We'll start by adding the digits 0 & 7 in column 4 and get 7.

So, 51 + 7702 = 7753.

